Thanks for the response.

I read through the information, but it did not answer the basic question of whether once Windows is installed in a BIOS RAID setting, the BIOS can be changed to ACHI.

The reason I am asking this question is that the SAMSUNG Magician utility requires ACHI to perform certain functions.

RodeoGeorge

I ran testing with Magician just this past week and saw no benefit when it came to real time performance.
Since then, I followed that guide in making bios and OS tweaks to optimize both of my 850 Evo's.
I'm pleasantly pleased with the overall results.

If you're adamant about running Magician, I'm 95% certain that you will need to re-install Windows in ACHI mode.

I think you are correct in that I'm not going to gain anything changing to ACHI so that Samsung Magician can be fully utilized.

Just a FYI to anyone reading this thread. I googled changing Windows 8.0 Pro from RAID to ACHI and found the following:

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Here's the ultimate fix 🙂 the idea behind is the Windows 8 safe mode takes care of loading the right driver and modifying the registry! Here's how:
- Run msconfig (right click far left bottom corner of desktop then left click run, type msconfig).
- Click boot tab, mark safe boot, restart, change to AHCI in BIOS, boot, Windows boots in safe mode.
- Run msconfig again, boot tab unmark safe boot, restart PC.
- PC works fine. Don't mess with regedit you only need to boot in safe mode to fix this, very simple.
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I tried doing the above, and the computer did boot back up into Windows, HOWEVER, there was an ATKEY_cmd.exe load error, AND the drivers for the LAN and Audio did not load.

I did a disk image using Acronis before trying the above, and then just reloaded the image after changing back to RAID.

Thanks for your suggestions and insight NemesisChild.

RodeoGeorge